But in 1950, there were only six science fiction films released in the United States.
The first of these was The Flying Saucer (available on DVD from Amazon for $5 and up), released on January 4, 1950, which means of course that it was filmed in 1949, just a few months after the first UFOs were seen over the mountains of Washington state.
Bill Warren, in his book Keep Watching The Skies, does not think much of The Flying Saucer.
The film is dull and thuddingly unimaginative.
In real life, flying saucers had been seen over a mountain in Washington in 1949. Film maker Mikel Conrad gets the idea for The Flying Saucer. It doesn't occur to him (at least in the movie) that this saucer could be from outer space. No - it is from a foreign power, and must be found for the United States.
The Flying Saucer is a spy movie, not really a science fiction movie. But if one accepts it on that premise (after all, why shouldn't the flying saucers people see be experimental craft from the US or Russia or China, and nothing to do with outer space at all? Asimov for one, while believing that there wer plenty of aliens in outerspace, believed the distances between planets was far too vast for aliens to come here and waste time kidnapping people for decades instead of just contacting us!)
But for $5 or so for a used copy...it deserves a look-see.
Here's the cast, as per the IMDB:
Mikel Conrad ... Mike Trent
Pat Garrison ... Vee Langley
Hantz von Teuffen ... Hans
Earle Lyon ... Alex Muller
Lester Sharpe ... Col. Marikoff
Russell Hicks ... Hank Thorn
Frank Darien ... Matt Mitchell
Denver Pyle ... Turner
Roy Engel ... Dr. Carl Lawton
Garry Owen ... Bartender
Virginia Hewitt ... Nanette
George Baxter ... Fred Burnside
Philip Morris ... Dreamland Bartender
Robert Boon ... Barge Captain